Hybrid Electrode Research Articles

Synergetic effect of a battery-like nickel phosphide and a pseudocapacitive cobalt phosphide electrodes for enhanced energy storage

The development of high energy density supercapacitors is essential due to the increasing concerns about environmental pollution and the demand for energy storage systems. Although the commercial electrode for the supercapacitor is composed of an electric double layer capacitance (EDLC)-based carbon materials, other transition metal-based pseudocapacitive or battery-like materials have also been investigated by many researchers; the energy density value of these devices need subsequent improvement. In this study, we developed hybrid electrodes composed of metal-organic frame-derived cobalt phosphide (CoP) and electrodeposited nickel phosphide (NiP) materials on nickel foam (NF). This hybrid electrode shows a high energy density value due to the combination of a pseudocapacitive CoP with a battery-like NiP material. The NiP/CoP@NF electrode exhibits an enhanced specific capacitance of 1154.4 F g−1 at 1 A g−1, which are much higher than those of individual NiP@NF and CoP@NF. The asymmetric supercapacitor (ASC) exhibits an excellent energy density of 27.7 Wh kg−1 at a power density of 800 W kg−1 and long-term stability with capacitance retention of 86.36 % for up to 10,000 cycles, representing their remarkable energy storage performance when compared to the previously reported NiCoP-based ASCs.

4-Cyanophenol herbicide sensor using multi-walled carbon nanotube embedded dual-microporous polypyrrole nanoparticles as metal-free and environmentally friendly hybrid electrode.

A highly sensitive 4-cyanophenol (4-CP) sensor was fabricated using multi-walled carbon nanotube (MWCNT)-embedded dual-microporous polypyrrole nanoparticle-modified screen-printed carbon electrodes (SPCE/DMPPy/MWCNT). The well-defined dual pores of DMPPy and MWCNT (~ 0.53 and ~ 0.65nm) acted as good analyte absorption agents (shortening the ion diffusion path) and conducting agents (reducing the internal electron-transfer resistance). This enhanced electrical conductivity resulted in the improved electro-oxidation of 4-CP. A higher sensitivity (19.0 μA μM-1cm-2) and lower limit of detection (0.8nM) were achievedwith a wide detection range of 0.001-400µM (R2 = 0.9988). The proposed sensor exhibited excellent recovery of 4-CP in real-world samples. Therefore, the SPCE/DMPPy/MWCNT sensor is regardedhighly suitable for rapidly detecting 4-CP.

Ultrafine nanoparticles of tin-cobalt-sulfide decorated over 2D MXene sheets as a cathode material for high-performance asymmetric supercapacitor

The design of electrode materials for improved electrochemical properties and stable geometric configuration is known as effective research in developing the electrochemical capability of supercapacitors (SCs). However, there is a difficulty in designing innovative composite material with excellent electrical conductivity and superior specific capacity by way of low cost and easy synthesis process. Herein, for the first time, a stable Sn-Co-S/MXene hybrid material is fabricated through the electrochemical assembly by combining positively charged ultrafine Sn-Co-S nanoparticles (NPs) and negatively charged 2D Ti3C2Tx (MXene) sheets due to electrostatic interaction. The Sn-Co-S/MXene hybrid material has displayed excellent electrochemical performance with an ultrahigh specific capacity of 305.71 mA h gm−1 at 1 A g−1 and capacity retention of 94.8% after 10, 000 charge–discharge cycles. The Sn-Co-S/MXene hybrid material of high electrochemical performance has improved charge transfer kinetics during the charge–discharge process, due to the synergistic coupling effect between ultrafine Sn-Co-S nanoparticles and MXene sheets. Furthermore, the Sn-Co-S/MXene//activated carbon (AC) asymmetric supercapacitor (ASC) device has been configured with the assistance of Sn-Co-S/MXene as cathode and AC as anode materials. The Sn-Co-S/MXene//AC ASC device exhibits a stable potential window of 1.7 V, a high specific capacitance of 108.50F g−1 at 1 A g−1, and an energy density of 43.55Wh kg−1 at a power density of 0.83 kW kg−1. This study validates the design and application of highly electroactive Sn-Co-S/MXene hybrid electrode material for ultrastable asymmetric supercapacitors.

One-pot synthesis of NiO-MnCo2O4 heterostructure hollow spheres via template-free solvothermal method for high-performance supercapacitors

Supercapacitors employ transitional metal oxides as pseudocapacitive materials have drawn great attention owing to their prominent energy storage performances, but most of them are concentrate on simplex metal oxides. In this work, we reported a novel electrode material for supercapacitors composed of NiO-MnCo2O4 heterostructure hollow spheres via a facile and one-pot route. The resulting hybrid electrode material demonstrates a high specific capacity of 660 C g−1 at 1 A g−1. An assembled hybrid supercapacitor based on this unique heterostructure hollow spheres as positive electrode and nitrogen doped hierarchically porous carbon as negative electrode indicates a favorable energy density of 40 Wh kg−1 at 750 W kg−1 and long cycling lifespan of nearly 90% capacity retention rate after 5000 cycles. This work not only produces a competitive electrode material for energy storage devices but also offers a feasible strategy for producing complex transitional metal oxides materials with high capacitive performance.

Advanced Electrode Coatings Based on Poly-N-Phenylanthranilic Acid Composites with Reduced Graphene Oxide for Supercapacitors.

The electrochemical behavior of new electrode materials based on poly-N-phenylanthranilic acid (P-N-PAA) composites with reduced graphene oxide (RGO) was studied for the first time. Two methods of obtaining RGO/P-N-PAA composites were suggested. Hybrid materials were synthesized via in situ oxidative polymerization of N-phenylanthranilic acid (N-PAA) in the presence of graphene oxide (GO) (RGO/P-N-PAA-1), as well as from a P-N-PAA solution in DMF containing GO (RGO/P-N-PAA-2). GO post-reduction in the RGO/P-N-PAA composites was carried out under IR heating. Hybrid electrodes are electroactive layers of RGO/P-N-PAA composites stable suspensions in formic acid (FA) deposited on the glassy carbon (GC) and anodized graphite foil (AGF) surfaces. The roughened surface of the AGF flexible strips provides good adhesion of the electroactive coatings. Specific electrochemical capacitances of AGF-based electrodes depend on the method for the production of electroactive coatings and reach 268, 184, 111 F∙g-1 (RGO/P-N-PAA-1) and 407, 321, 255 F∙g-1 (RGO/P-N-PAA-2.1) at 0.5, 1.5, 3.0 mA·cm-2 in an aprotic electrolyte. Specific weight capacitance values of IR-heated composite coatings decrease as compared to capacitance values of primer coatings and amount to 216, 145, 78 F∙g-1 (RGO/P-N-PAA-1IR) and 377, 291, 200 F∙g-1 (RGO/P-N-PAA-2.1IR). With a decrease in the weight of the applied coating, the specific electrochemical capacitance of the electrodes increases to 752, 524, 329 F∙g-1 (AGF/RGO/P-N-PAA-2.1) and 691, 455, 255 F∙g-1 (AGF/RGO/P-N-PAA-1IR).

A novel strategy for high energy density supercapacitors: Formation of cyanuric acid between Ti3C2Tx (MXene) interlayer hybrid electrodes

Ti3C2Tx (MXene) are attractive for electrode materials because of their high electrical conductivity, abundant interlayer ions and low density. However, the low energy density hinders its commercial application. Herein, a novel N-doped Ti3C2Tx MXene is synthesized by introducing a small organic molecule dicyandiamide (DCD) to tune the complex terminals. DCD can be inserted into the layers of Ti3C2Tx nanosheets while forming melamine by catalyst-free trimerization reaction. Then, melamine is converted into gt-C3N4 through high-temperature sintering. Finally, gt-C3N4 is oxidized to cyanuric acid (CA) through simple hydrothermal reaction. The prepared Ti3C2Tx/CA composite electrode exhibits up to 4.8 at.% nitrogen doping and has a stable triazine ring structure. It is also shown that the Ti3C2Tx/CA composite electrode has high specific capacitance and excellent cycling stability. More notably, it achieves an energy density of 51.1 Wh kg−1 at a power density of 2000 W kg−1, which exceeds the energy density of MXene based electrodes reported in the current literature. This excellent performance is attributed to the unique hydroxyl structure of the CA terminal and the excellent symmetry of CA in the composite electrode. In aqueous electrolytes, CA can form short chains during charging and the formation of short chains enables the storage of electrons and further provides a large number of new pseudocapacitive reaction sites for MXene. At the same time, the high electronegativity of the N and O atoms in CA also increases the electric double layer capacitor of the composite electrode to a certain extent, thus resulting in a high energy density of the composite electrode.

Dynamic phase evolution of MoS3 accompanied by organodiselenide mediation enables enhanced performance rechargeable lithium battery

Considerable efforts have been devoted to Li-S batteries, typically the soluble polysulfides shuttling effect. As a typical transition metal sulfide, MoS2 is a magic bullet for addressing the issues of Li-S batteries, drawing increasing attention. In this study, we introduce amorphous MoS3 as analogous sulfur cathode material and elucidate the dynamic phase evolution in the electrochemical reaction. The metallic 1T phase incorporated 2H phase MoS2 with sulfur vacancies (SVs-1T/2H-MoS2) decomposed from amorphous MoS3 achieves refined mixing with the "newborn" sulfur at the molecular level and supplies continuous conduction pathways and controllable physical confinement. Meanwhile, the insitu-generated SVs-1T/2H-MoS2 allows lithium intercalation in advance at high discharge voltage (≥1.8 V) and enables fast electron transfer. Moreover, aiming at the unbonded sulfur, diphenyl diselenide (PDSe), as a model redox mediator is applied, which can covalently bond sulfur atoms to form conversion-type organoselenosulfides, changing the original redox pathway of "newborn" sulfur in MoS3, and suppressing the polysulfides shuttling effect. It also significantly lowers the activation energy and thus accelerates the sulfur reduction kinetics. Thus, the insitu-formed intercalation-conversion hybrid electrode of SVs-1T/2H-MoS2 and organoselenosulfides realizes enhanced rate capability and superior cycling stability. This work provides a novel concept for designing high-energy-density electrode materials.

Quick-to-synthesize hybrid electrodes composed of activated carbon cloth with Co/Fe-based films as bifunctional electrocatalysts for water splitting

Hybrid electrodes have recently been investigated as attractive alternatives to noble-metal-based electrocatalysts for hydrogen production by water splitting. Herein, we propose an electrode composed of an oxidized carbon cloth with an electrodeposited bimetallic Co/Fe-based film. By optimizing the electrodeposition conditions and applying electrochemically activated carbon cloth as a substrate, one can prepare a free-standing noble-metal-free electrocatalytic electrode with high bifunctional electrocatalytic activity in hydrogen and oxygen evolution from alkaline solution. The developed Fe0.25Co0.75 electrode requires overpotentials of 245 mV for HER and 360 mV for OER at high current densities of −100 and 100 mA cm−2, respectively. Furthermore, its overall synthesis time from commercially available raw materials is only approximately 20 min. The electrode material was used as both a cathode and an anode in the model electrolyzer, which can deliver 10 mA cm−2 of current density at 1.66 V without loss of activity during 100 h of performance.

Fabrication of Large-Area, Affordable Dual-Function Electrochromic Smart Windows by Using a Hybrid Electrode Coated with an Oxygen-Deficient Tungsten Oxide Ultrathin Porous Film.

Electrochromic (EC) devices are not commercialized extensively owing to their high cost. The best large-area devices in the market suffer from not reaching a distinct dark-colored state. These devices appear more like a blue tinted glass. While a better performance demands the use of appropriate components, the cost-effectiveness of such components is crucial for commercialization. Specifically, the utilization of cost-effective electrodes, thin WO3 coatings, and inexpensive electrolytes are essential for reducing the cost of EC devices. Here, we report a high-performing porous WO3 thin film (∼130 nm) achieved by optimizing the DC sputtering process parameters. This way, an affordable dual-function EC energy-storage device was fabricated, showing 84% transmittance modulation and a high power density of 3036 mW/m2, thus functioning simultaneously as a transparency switching energy-storage device. With a large-area (900 cm2) device, we have demonstrated that the need for expensive ITO electrodes and Li+ ion-based electrolytes can be eliminated by using a hybrid electrode (ITO/Al-mesh) and multivalent Al3+ ion-based electrolytes while not compromising the device performance. The findings of this study may revolutionize the EC device industry and their commercialization owing to inexpensive ingredients and scalable processing.

Synthesis and electrochemical performance of rGO wrapped mixed metal oxide and sulfide nanocomposite for superior energy storage applications

Reduced graphene oxide (rGO) is added to TiO2 and TiS2 to develop several hybrid electrode materials, including rGO/TiO2, rGO/TiS2, and rGO/TiO2/TiS2 to enhance the electrochemical performance. SEM/EDX, TEM, XRD, XPS, and Raman techniques are used to study the resulting hybrid electrode materials. The capacitance and cycling capacity of the synthesized rGO/TiO2, rGO/TiS2, and rGO/TiO2/TiS2 electrode materials are assessed using galvanostatic and cyclic voltammetry testing. The rGO/TiO2/TiS2 exhibits higher electrochemical performance (726 mA h/g) at 20 mV/s, among the investigated composites. The rGO/TiO2/TiS2 electrode was found to have R ct value of 20.4 Ω.cm2. These values indicate that the rGO/TiO2/TiS2 has a much lower resistance, which may be the primary cause of the outstanding electrochemical properties of the rGO/TiO2/TiS2. The retention capacity of 97.93% at 1 A/g upto10,000 cycles shows that this rGO/TiO2/TiS2 hybrid electrode also exhibits good cycling stability. The rGO/TiO2/TiS2 composites’ respective energy and power densities are determined to be 682 Wh/kg and 5073 W/kg. Due to the synergistic interaction between TiS2, rGO, and TiO2, the rGO/TiO2/TiS2 hybrid is demonstrated to be a superior anode material in supercapacitors. Therefore, the newly fabricated rGO/TiO2/TiS2 nanocomposite could be used as the potential material for energy storage applications.

An integrated oxygen electrode derived from a flexible single-walled carbon nanotube film for rechargeable Zn-air batteries produced by electropolymerization

The development of low-cost, high-activity, and durable integrated bifunctional flexible air electrodes for use in Zn-air batteries is both challenging and important. We report a simple and scalable electropolymerization method used to prepare an electrode material comprising heavily N-doped carbon covering single-walled carbon nanotube (N/C-SWCNT) networks. The resulting core/shell structure of the hybrid electrode enabled the flexibility, mechanics, and three-dimensional interconnected porous structure of SWCNT films while containing abundant pyridinic N, which provided excellent catalytic activity for both the oxygen reduction and evolution reactions (overpotential gap = 0.76 V). A binder-free Zn-air battery using the N/C-SWCNT film as an oxygen electrode was assembled and showed a high peak power density of 181 mW/cm2, a high specific capacity of 810 mAh/g and stable discharge‒charge cycling performance. We also constructed a flexible solid-state Zn-air battery featuring not only a high power density of 22 mW/cm2 but also good flexibility and stability.

Experimental and computational investigation on the charge storage performance of a novel Al2O3-reduced graphene oxide hybrid electrode

The advancements in electrochemical capacitors have noticed a remarkable enhancement in the performance for smart electronic device applications, which has led to the invention of novel and low-cost electroactive materials. Herein, we synthesized nanostructured Al2O3 and Al2O3-reduced graphene oxide (Al2O3-rGO) hybrid through hydrothermal and post-hydrothermal calcination processes. The synthesized materials were subject to standard characterisation processes to verify their morphological and structural details. The electrochemical performances of nanostructured Al2O3 and Al2O3- rGO hybrid were evaluated through computational and experimental analyses. Due to the superior electrical conductivity of reduced graphene oxide and the synergistic effect of both EDLC and pseudocapacitive behaviour, the Al2O3- rGO hybrid shows much improved electrochemical performance (~ 15-fold) as compared to bare Al2O3. Further, a symmetric supercapacitor device (SSD) was designed using the Al2O3- rGO hybrid electrodes, and detailed electrochemical performance was evaluated. The fabricated Al2O3- rGO hybrid-based SSD showed 98.56% capacity retention when subjected to ~ 10,000 charge–discharge cycles. Both the systems (Al2O3 and its rGO hybrid) have been analysed extensively with the help of Density Functional Theory simulation technique to provide detailed structural and electronic properties. With the introduction of reduced graphene oxide, the available electronic states near the Fermi level are greatly enhanced, imparting a significant increment in the conductivity of the hybrid system. The lower diffusion energy barrier for electrolyte ions and higher quantum capacitance for the hybrid structure compared to pristine Al2O3 justify improvement in charge storage performance for the hybrid structure, supporting our experimental findings.

MOF-Derived Ultrathin NiCo-S Nanosheet Hybrid Array Electrodes Prepared on Nickel Foam for High-Performance Supercapacitors.

At present, binary bimetallic sulfides are widely studied in supercapacitors due to their high conductivity and excellent specific capacitance (SC). In this article, NiCo-S nanostructured hybrid electrode materials were prepared on nickel foam (NF) by using a binary metal-organic skeleton as the sacrificial template via a two-step hydrothermal method. Comparative analysis was carried out with Ni-S and Co-S in situ on NF to verify the excellent electrochemical performance of bimetallic sulfide as an electrode material for supercapacitors. NiCo-S/NF exhibited an SC of 2081 F∙g-1 at 1 A∙g-1, significantly superior to Ni-S/NF (1520.8 F∙g-1 at 1 A∙g-1) and Co-S/NF (1427 F∙g-1 at 1 A∙g-1). In addition, the material demonstrated better rate performance and cycle stability, with a specific capacity retention rate of 58% at 10 A∙g-1 than at 1 A∙g-1, and 75.7% of capacity was retained after 5000 cycles. The hybrid supercapacitor assembled by NiCo-S//AC exhibited a high energy density of 25.58 Wh∙kg-1 at a power density of 400 W∙kg-1.

Minimizing the volume expansion by a self-standing reduced graphene oxide/silicon nanoparticles/copper mesh hybrid electrodes for enhanced lithium-ion batteries

In this study, we develop a self-standing hybrid electrode that composed of the tandem structured Si nanoparticles (NPs)/reduced graphene oxide (RGO)/copper mesh (RGO/Si/Cu) by a facile spray method. As the anode for lithium-ion batteries (LIBs), it provides a highly reversible specific capacity of 1070.2 mAh g−1 at 1 A g−1 after 400 cycles. Even at 2 A g−1, the capacity is still 1005.1 mAh g−1. The electrochemical measurement features that the charge/discharge resistance of the RGO/Si/Cu anode is only 65 Ω, which is far less than that of RGO/Si (990 Ω). Further, the high Li+ diffusion coefficient is demonstrated in RGO/Si/Cu. Besides, the diffusion-controlled process dominates the Li+ storage in RGO/Si/Cu. Most importantly, the volume change of RGO/Si/Cu is as low as ~27 %, highlighting the superiority of this novel structure.

In-situ synergistic W18O49/Ti3C2Tx heterostructure as negative electrode for high energy density supercapacitors

Ti3C2Tx has attracted great attention as negative electrode material of supercapacitors owing to its high metallic conductivity, abundant surface terminations, and suitable potential range. However, the inevitable restacking of two-dimensional nanosheets dramatically restrain the electrochemical performances of individual Ti3C2Tx electrodes. In this work, interface-induced in-situ growth strategy was developed to construct W18O49/Ti3C2Tx heterostructures through a simple solvothermal reaction. The optimized W18O49/Ti3C2Tx hybrid electrode delivered a high specific capacitance of 472.6 F g−1 at 1 mV s−1 and retained 73.3% of its initial capacitance under 100-fold scan rate. The asymmetric supercapacitor assembled with W18O49/Ti3C2Tx negative electrode and RuO2@CC positive electrode exhibited a high energy density of 29.6 Wh kg−1 and maximum power density of 7.0 kW kg−1. In sum, the designed negative electrode materials look promising for future use in high-energy-density supercapacitors.

Ni3S4 nanoparticle decorated Mn doped Co(OH)2 nanosheets as electrodes of hybrid supercapacitors with high energy density and long-term cycle stability

Due to their outstanding electrochemical properties, transition metal sulfides and hydroxides are often used as high-performance electrode materials for supercapacitors. The Mn-doped Co(OH)2/Ni3S4 electrode material in this study, due to the synergistic reaction mechanism among Co(OH)2 and Ni3S4 and the increased active sites by the addition of Mn, the Mn-Co(OH)2/Ni3S4 exhibits excellent electrochemical property. The electrochemical performance of the Mn-Co(OH)2/Ni3S4 hybrid electrode was measured in an electrode cell made of 2 M KOH solution, showing a superior specific capacitance of 1107.0 C g−1 at 0.5 A g−1, in addition to the excellent capacity retention rate at 10 A g−1 is 72.7 % of that at 1 A g−1. The performance of the hybrid supercapacitor (HSC) assembled with Mn-Co(OH)2/Ni3S4 compound and activated carbon (AC) was measured under the same electrolyte conditions, anwell-specificific capacity (157.2 F g−1 at 0.5 A g−1) was achieved, along with superior long-term stable charge/discharge capability (88.9 % of the original specific capacity after 35,000 cycles at 8 A g−1). Meanwhile, the most practical application is when the power density of 410.4 W kg−1, the assembled HSC device has an energy storage capacity of 58.8 W h kg−1, revealing that the developed Mn-Co(OH)2/Ni3S4 has great application potential for supercapacitors in the future.

Phosphomolybdic acid embedded into biomass-derived biochar carbon electrode for supercapacitor applications

In high-performance, clean, safe, and cost-effective ways, supercapacitors are among the most promising ways to store and release nonfossil energy. In recent years, renewable biomass-derived activated carbon has been explored as a potential option for electrode material. It restricts their specific capacitance despite being environment-friendly and possessing intrinsic mechanical strength. In order to overcome this limitation and preserve all other properties, we are infusing polyoxometalate into the activated carbon; this increases specific capacitance with its fast reversible redox behaviour and preserves the carbon’s characteristics. Beside suffusing phosphomolybdic acid (PMA) into biomass waste material, such as orange peel-derived activated carbon (OPAC), a new hybrid material (OPAC-PMA) was developed. The nanohybrid design was revealed by structural and morphological research, which showed high interfacial contact, allowing polyanions to redox rapidly. The novel hybrid electrode material (OPAC-PMA) has a capacitance value of 66% higher than the bare OPAC electrode. A further study showed that OPAC-PMA composite showed 88.23% cycle stability in 0.5 M H2SO4 electrolyte at 6 A g−1 for 4000 cycles.

CsPbBr3/platinum and CsPbBr3/graphite hybrid photoelectrodes for carbon dioxide conversion to oxalic acid

CsPbBr3 halide perovskites have been recently received a lot of interest in the field of photo and electro catalysis, solar cells, and photodetectors due to their tunable band gap, large absorption coefficient and high carriers’ mobility. However, CsPbBr3 poor water stability limits its real application and the development of related devices. In this work, hybrid CsPbBr3/platinum (Pt) and CsPbBr3/graphite (C) photo-electrodes are employed, for the first time, in aqueous environment for the photo-electrochemical CO2 conversion to liquid products. Hybrid photo-electrodes were prepared depositing CsPbBr3 by spin coating and sputtering Pt or C on top of it to obtain a homogeneous protective layer with the same thickness. Thanks to the Pt and C layers, the instability of the perovskite in water environment is overcome and the new hybrid electrodes obtained still showed the ability to absorb light in the visible region producing photocurrent. The as-obtained photo-electrodes demonstrated energy band values suitable to reduce carbon dioxide by photo-electrocatalytic reaction in water environment. As main results, these hybrid electrodes produced complex organic molecules such as oxalic acid with Faradic efficiencies close to 44% (at −0.8 V vs Ag/AgCl) using graphite in combination with CsPbBr3.

Open 3D structure of Ni2−xSnxP/C microflowers electrodes assisted by ion-exchange in metal-organic skeleton for battery-supercapacitor hybrids

Transition metal phosphides are promising electrode materials for battery-type supercapacitors. Herein, the Ni2−xSnxP/C microflowers electrode materials are synthesized through ion-exchange of metal-organic frameworks and subsequent calcination processes. The introduction of Sn species significantly alters the microstructure of Ni2−xSnx-MOF and Ni2−xSnxP/C. The optimum Ni1.6Sn0.4P/C exhibits 3D (3-dimensional) open flower-like microstructures, which are composed of large quantities of nanorods. As battery-supercapacitor hybrid electrode materials, the as-prepared Ni1.6Sn0.4P/C exhibits an excellent specific capacity of 839.6 C g−1 at the current density of 1 A g−1 and superior capacity retention in a three-electrode system. Moreover, the assembled Ni1.6Sn0.4P/C//AC asymmetric supercapacitor demonstrates a high energy density of 59.3 Wh kg−1 at the power density of 750 W kg−1, and good cycling stability with 92% capacity retention after 5000 cycles at current densities of 10 A g−1. Therefore, the Ni1.6Sn0.4P/C with flower-like microstructures are expected to be an ideal battery-type electrode material for high-performance energy storage devices in the future.

Polyphosphazene Based Inorganic‐Organic Hybrid Cathode Containing Pyrene Tetraone Sides for Aqueous Zinc‐Ion Batteries

AbstractAqueous rechargeable zinc‐ion batteries (ARZBs) are intriguing for electrochemical energy storage applications because of their safety and cost‐effectiveness. Regarding cathode materials, rapid development has been observed with the organic‐based cathode materials that offer much higher structural integrity upon successive (de‐)insertion of charge carries ions. Even though promising results demonstrated with organic electrodes, they still suffer from the short cycle‐life due to their discharge products solubility in electrolyte. Herein, electrochemical performance and charge storage mechanism of the synthesized polyphosphazene‐based inorganic‐organic hybrid electrode containing pyrene‐4,5,9,10‐tetraone (PTO) redox active lateral group, poly[(bis(2‐amino‐4,5,9,10‐pyrenetetraone)], abbreviated as (PPAPT), were investigated in ARZBs. The charge storage mechanism of PPAPT was examined by variousex‐situ[Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), scanning electron microscopy and energy dispersive X‐ray spectroscopy (SEM‐EDS), X‐ray photoelectron spectroscopy (XPS)] andin‐situ[pH change with bromocresol green indicator and electrochemical quartz crystal microbalance (EQCM)] characterization techniques as well as computational density functional theory (DFT) revealing that the PPAPT electrode (de‐)coordinates both zinc and proton. The electrode and its discharge product are insoluble in the electrolyte demonstrated by UV‐vis analysis and exhibited a stable cycling performance with a discharge capacity of 125.4 mAh g−1after 1000 cycles at a current density of 10 C.